The invention relates to a one-piece electro-cathether with two independent and actively-engaging electrodes.
In the clinical practice of permanent cardiac stimulation (artificial pacemaker implantation), which is designed to prevent auriculo-ventricular and sinoatrial block, and in other connected types of therapy (treatment of sinoatrial node diseases, of brady/tachy-syndromes, and of hypo- and hyper-kinetic arrhythmia) there is an increasing trend toward so-called `physiological` stimulation whereby it is sought to reproduce the natural auriculo-ventricular sequence, and to reconstruct the correct hemodynamic sequence, and, in cases where atrial activity still continues, to maintain the state of dependence on such metabolic signals as influence the pacemaking activity of the sinoatrial node.
To this end, use is made of a stimulator capable of receiving and acknowledging an electrical atrial depolarization signal by way of an electrode implanted in the atrium; the signal is amplified and exploited for the purpose of synchronizing a pulse generator which, following a preset delay calculated to match physiological parameters (100 to 200 msec), emits an electrical impulse such as will stimulate the ventricle by way of an electrode implanted therein; thus one reconstructs the natural auriculo-ventricular contractile sequence.
In the event of there being no atrial signal, or that the frequency available is lower than will match the sensitivity of the stimulator, a second pulse generator is utilized to stimulate the atrium by way of an electrode implanted therein, in the same way as for the ventricle, so as to maintain the physiological auriculo-ventricular sequence.
The use of such methods in practice has been significantly restricted thus far by the need for insertion of two catheter electrodes, one in the ventricle, the other in the atrium; this operation is rendered problematic by reason, amongst other considerations, of the smoothness of the inner wall of the chamber and the attendant difficulties of firm anchorage and stable contact.
The object of the invention is to prevent the difficulties thus outlined by adoption of a single catheter incorporating two independent electrodes.